Transcript for George Zimmerman's Wife on Their Marriage, Trayvon Martin

Shelly zimmerman stood by her husband's side for the verdict after the explosive trial. when she was sentenced to a year's probation and community service to a judge about the couple's finances. As we learned later, the united front with the couple who spoke in code to hide their&#231;&#243; assets now seems broken. Reporter: Shelly zimmerman sat quietly by as her husband was accused and tried for murder. Today, she is finally speaking out about her husband, george zimmerman, and their relationship. I can't tell you how many nights I have gone -- or laid awake at night just thinking i wish to god these circumstances had been different. Reporter: Those circumstances, shelly says, began even before the shooting death of 17-year-old trayvon martin. In an exclusive interview, shelly says she can't explain what was going through her husband's head the night he got into a fight with martin, because she was not home. I was staying at my father's house. We had gotten into an argument the night before. And I left. Reporter: This 26-year-old sat down with kristi o'connor, an investigative reporter who is writing a book on the story. Shelly still stands by george. Do you think george is capable of having profiled trayvon martin and killed him on purpose? No. Why not? That is just not his way. Reporter: On february 26th, 2012, trayvon martin was walking back to a house in a gated community in sanford, florida, where he and his father were staying. Trayvon caught the attention of the neighborhood watchman, who called police. This guy looks like he is up to no good, or is on drugs or something. Reporter: A fight broke out. That is when he tried to slam me down. Reporter: Zimmerman fired one gunsh gunshot, and trayvon martin was killed. Zimmerman claimed he shot in self defense and was acquitted of manslaughter. After his acquittal, his attorney says he is now an outcast. Unfortunately, even though he did nothing but protect himself that night, the way the things were visited on him, by the way the case was handled, made him a pariah. Reporter: But shelly stood by him, even as death threats came. There had been so many scary ones, like if george gets acquitted, you will find him hanging in a tree. Reporter: The couple was forced to run. We have been pretty much gypsies for the past year and a half. We lived in a 20-foot trailer in the woods. Scared every night that a somebody was going to find us, and that we would be out in the woods alone. And that it would be horrific. Reporter: Shelly says she felt like she was living in a fish bowl, ripple effects from martin's death extended far beyond the original trial. Sparking massive protests across the country. Justice, now! Reporter: And shelly zimmerman found herself caught up in the ripples. She admits she lied for george at his bond hearing, hiding how much money they had from a judge. Why did you lie? Fear. Reporter: Of? Many things. There was just the fear of people knowing how much money we had come into, and that was a lot of money for us. Reporter: When george was arrested, the donations began to pour in, his lawyer said about $200,000, to help pay for his mounting legal expenses. Their reaction was captured in taped jail house calls. After that happened yesterday, he said like -- so many people, kept crashing. Reporter: But also signs of a wife's growing ambivalence. After this is over, you're going to be able to have a great life. We will. Yeah, we will. Reporter: Prosecutors say the couple used a code language to try to keep their conversations about their finances from authorities. For example, calling pay pal peter pan. Ken is going to go from the peter pan. Reporter: While keeping track of how much was in the account. Totaling everything, how much we're looking at. Like $155. Reporter: Prosecutors say that is code for $155,000. But only days later, shelly was pleading poverty. You all have no money, is that correct? To my knowledge, that is correct. Reporter: Were you under any pressure from anyone, george, his team, to lie? I'm not going to go into that right now. Reporter: Wednesday, in the same courthouse where her husband was acquitted, shelly pled guilty to a misdemeanor perjury charge. You know, I can rationalize a lot of reasons for why I was misleading. But the truth is that I knew that I was lying. Reporter: She has been sentenced to one year probation and 100 hours of community service. I answer to a higher power. And I could not live with myself if I didn't just completely come clean. We, the jury, find george zimmerman not guilty. Reporter: Yet even though she was there as her husband's verdict was read, george was not in court when she made her plea. Now, we're getting a closer look into their relationship. A hint that the couple's marriage may be in trouble. Reporter: Did you want him to be in court to support you? I always want my husband's support. Reporter: Since the acquittal in july, george has been off the radar. But just last week, george visited a florida gun manufacturing plant. It is the same company that made the gun he used to shoot martin. Do you think it was the right think to do? No, I just think that he is under -- or he has been kind of living in a pressure cooker. And he is doing or thinking some things that none of us can maybe understand right now. Reporter: It is unclear how much time they're still spending together as a couple. Are you together? I'm not going to answer that. Reporter: Has this whole experience hurt your relationship? Yes. Reporter: Do you want to have children? Do you want to stay married? Of course, I want to have children and stay married. Reporter: With george? That is -- something I'm going to have to think about. Reporter: Whether it is with george or not, shelly says she is determined to move forward. I want people to realize that I am a human being who is full of flaws. Reporter: Part of that process, she says, delivering a message to trayvon's parents. If I could speak to them, i would say that I'm so deeply sorry for their loss. And I can't even begin to understand the grief that a parent experiences when they lose a child. Reporter: For "nightline,". They declined to comment. And coming up next, why all

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